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Defining Newmann's boundary conditions in COMSOL
Posted 13 ott 2015, 12:34 GMT-4 Interfacing, Parameters, Variables, & Functions Version 5.1 0 Replies
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I am new in COMSOL, and having a lot of trouble getting used to the pre-defined form of the equations.
In addition, since I can't find any good introductory tutorials (1D for example...) for LiveLink or COMSOL, I would be glad to receive some sort of guidance-
I would like to know if there is someway to solve the Cahn-Hilliard equation (for example) , with Newmann's BC :
u_t = (u^3 - u - 0.2^2 * u'' ) ''
u' = u''' = 0 on both boundaries of the interval.
What I have tried is:
defining v=u'', and rewriting the equation above in a matrix form, using "Coefficient form" or "general form" time dependent PDE.
Next, when I need to set the boundary conditions, I run into trouble-
even the flux/source kind of boundary condition, isn't exactly Newmann's BC, so I have no idea how to define such a BC (it is actually a Newmann's BC on the flux! and not on the function itself ) .
My questions are:
1. How can I define Newmann's BC in COMSOL ?
2. Is there any way to write my equations in MATLAB (not in the predefined form of COMSOL) , including the appropriate BC, and then importing these definitions into COMSOL ? If so, where can I find such an example?
Will you please help me out with this?
Thanks in advance
Hello Joshua Hoffman
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